What is the primary purpose of forcing air into a sewer system during smoke testing?

The primary purpose of forcing air into a sewer system during smoke testing is to establish an airflow within the system. This process helps to identify any leaks or illicit connections within the sewer infrastructure. When air is introduced into the system, it travels through the sewer lines and out through any openings, allowing technicians to visualize where smoke escapes. If there's a break, crack, or connection to a storm drain, the smoke will be visible, indicating these problem areas that may need further investigation and repair. This reliable method is often used because smoke is easily detectable and can quickly highlight issues that might not be evident through visual inspection alone.